1. Field of the Invention
The present invention relates to an image processing apparatus, image processing system, and image processing method. Particularly, the present invention relates to an image processing apparatus, image processing system, and image processing method for analyzing an input image.
2. Description of the Related Art
Recently, very precise images can be printed thanks to the development of an image processing technology and computer graphic technology. However, specific kinds of blur appears in a printed product, depending on the printing method (process) and printing medium (for example, paper). The occurrence of a blur on a printed product stems from a variety of causes. When ink permeates a sheet along the fibers of the paper comprising the sheet, or when ink cannot be fixed on the paper surface under the influence of the non-affinity of a substance contained in paper for the ink solvent, ink scattering, a blur on the transfer drum, misalignment on the transfer drum in exposure, or the like appears.
An image blur arises from various causes dependent on a printing method adapted in a printer.
For example, in an electrophotographic printer which prints (renders) an image by exposing a photosensitive material with a light beam, the spot of the light beam on the photosensitive material surface slightly spreads from a proper one due to an optical error or the like, and exposes even a portion that is not supposed to be exposed. The spread size of the spot of the light beam sometimes differs between beams corresponding to exposure in R (Red), G (Green), and B (Blue) colors. If the exposure amount at a portion which is not supposed to be exposed reaches a certain amount due to the spread of the light beam spot, the photosensitive materials unnecessarily develop the color. This results in a detail loss at a minute and highlighted portion such as a thin line, or a color blur or the like arising from the difference in the sizes of respective color light beams in a thin outline character formed in a high-density area, black and white thin stripes, or the like.
In an inkjet printer, ink dots spread undesirably, due to an error of the discharged ink amount, and/or an ink blur or the like upon attachment of ink droplets to a printing medium. Further, a single ink droplet is divided into a plurality of droplets until it reaches a printing medium, and the droplets scatter on the printing medium. These causes generate a detail loss and color blur at a minute and highlighted printed portion.
Typographic printing suffers fatting caused by ink overflow.
Consequently, an image detail loss, image blur, and the like appear in a character, a thin line, a thin outline character, white ones of black and white thin stripes, a white minute point, and the like, causing a deterioration in the image quality. They stand out much more at a minute and highlighted portion in an image.
The detail loss and color blur can be suppressed to a certain degree by mp adjustment in shipment of a printing apparatus (printer) or the like. However, the detail loss and color blur of a thin line change depending on the apparatus state, and the lots of consumables including the photosensitive material, printing medium (for example, paper), developer, and ink. In addition, the optimum adjustment value changes according to users' preferences. At present, it is difficult to preferably suppress detail loss and color blur at a minute and highlighted portion in accordance with each apparatus and user.
There is disclosed a technique of suppressing image detail loss and color blur in a thin line character, a minute pattern, and the like in an image forming apparatus such as a digital photo printer, electrophotographic printer, or inkjet printer (for example, Japanese Patent Laid-Open No. 2007-104277).
However, measures are not taken against all kinds of printed products. For example, there is an image document suffering a blur as shown in FIG. 5.
When an image deteriorated by the above-mentioned blur or the like is input using a scanner, camera, or the like, even the blur is accurately read. The input image is faithful to an original one, but even unnecessary information is reproduced. For example, Japanese Patent Laid-Open No. 2000-36912 discloses a technique of correcting image deterioration by a scanner for the purpose of faithful reproduction.
The above conventional technique can perform line width control for a character image area, but cannot reduce an image blur or the like.
There has also been disclosed a technique of changing notch processing that is uniformly performed over an entire printed document in accordance with the resolution in image printing. In this technique, however, it is not determined whether an input image blurs, so an entire printed image has to be uniformly processed. If a printed image partially blurs, the blur cannot be effectively reduced.